Fiber optic cables include one or more optical fibers or other optical waveguides that conduct optical signals, for example carrying voice, data, video, or other information. Optical fibers are ordinarily susceptible to damage from water and physical stress. Without an adequate barrier, moisture may migrate into a fiber optic cable and weaken or destroy the cable's optical fibers. Without sufficient physical protection, stress or shock associated with handling the fiber optic cable may transfer to the optical fibers, causing breakage or stress-induced signal attenuation.
Fiber optic cables may incorporate one or more layers of armor under one or more layers of jacketing, including an outer jacket. The armor offers mechanical protection, such as crush and rodent resistance. A metallic armor can further facilitate locating a buried cable. The outer jacket covers the armor for environmental protection.
In many cable installations, a craftsperson, such as a field service technician, may seek access to optical fibers of a cable at a place other than at a cable end, such as at a midpoint along a cable span. In such circumstances, the craftsperson may strip the outer jacket from the armor as a step in gaining access to the delicate optical fibers within the cable core. Some of the cable's fibers may carry live traffic during the service procedure, and the craftsperson is faced with the intricate task of avoiding any damage to the fibers. Apart from severing a fiber, even a seemingly insignificant, inadvertent nick of a cable tube can lead to premature fiber failure.
Accordingly, cable designers seek to control adhesion between the jacket and the armor. Too little adhesion can not only weaken structural integrity but also result in an annular gap through which water can detrimentally migrate if the cable suffers damage. Too much adhesion can complicate field service operations that involve stripping the jacket.
Conventional technologies for controlling adhesion between the jacket and the armor are generally limited. One approach involves coating the armor with a polymer that adheres to the jacket but has a low cohesive strength to facilitate peeling the jacket from the armor. Another approach involves applying a hot-melt substance, such as atactic polyolefin polymer, between the jacket and the armor. Such conventional approaches can pose challenges in terms of supply availability, manufacturing complications, and consistent performance.
Accordingly, to address such representative deficiencies in the art, improved cable technology is needed for protecting optical fibers while facilitating service operations. Need exists for controlling coupling between adjacent elements of a cable, including cable armor and cable jacketing. Need exists for blocking flow of water between armor and a jacket of a cable. Further need exists for covering a cable with a jacket that can be readily stripped or peeled in the field without undue labor or complicated tools or without risking damage to delicate optical fibers of the cable. Further need exists for cable jacketing technology that is conducive to economical manufacturing. A capability addressing one or more of the aforementioned needs, or some related shortcoming in the art, would promote optical fibers for communications and other applications.